End of a relationship?

Lily

So the past few days my boyfriend has been awful and moody and I don't know why. We have a one month old daughter and he has a 3 year old son. Well lately his new thing is to say I only got with him so I could get a baby and all I care about is her. Yes, our daughter is my first priority and my whole day revolves around her. I exclusively breastfeed and she's only a month old. But if I only wanted a child then I would've left him once I got pregnant or was far enough along and Ive straight out told him this. It's starting to really make me mad. And now the most recent thing is that I'm not allowed to tell his son not to do anything or anything along those lines. Here's a little background on that: he started getting his son last year. Since he started getting him I have been the one to take care of him, bathe him, change him, put him to bed, get up with him, everything. Even when my boyfriend is out of work (he can't hold a job) and is home all day I'm still somehow stuck taking care of his son while he sits on his phone or sits in the garage or leaves. He doesn't watch his son or pay attention when hes doing something wrong so yes I have told him no and he needs to not do that and stop and I have given him timeouts when I'm watching him but this has never been a problem before. Hes not working so there's no excuse for any of this. Now my main thing, how the heck does the relationship work if I'm suddenly not allowed to do anything with his son or tell him anything. I grew up with step-parents and though they never disciplined us (spankings or groundings) they had full right to tell us no and to discipline us (within reason) as they were parent figures to us. His son has noticed by the way and is just awful to me, hits me, bites me, throws things at me, and so far he rarely gets in trouble for it. He's also horrible to my little siblings (pulls hair, hits, takes toys from them) and yet again if I or my mom don't yell at him or say something then he doesn't get in trouble. I'm at a loss.